Steam Flooding Research Articles

Gravity Drainage Visualization Experimental Study of Heavy Oil Reservoirs

Liaohe oilfield gravity drainage assisted steam flooding of heavy oil reservoir has made significant development effect, but the drain rule of condensate is unclear in the process of development. Heavy oil drainage microscopic visualization experimental study of using core model of glass etching, drainage process simulation of heavy oil reservoir and its influence factors were analyzed. Its method turns the drainage process of images into computer numerical signal through the image acquisition system, intuitive display flow pattern of drainage, and analyses the influence of homogeneity and the pressure differential regulation of drainage through the experimental data. The experiment results show that condensate around the steam chamber has a corresponding drainage channel, not uniform or diarrhea in the gravity drainage assisted steam flooding process. At the beginning of the drainage channels formation, the instantaneous drainage amount along with the change of pressure difference is not obvious. Instantaneous drainage amount increases with increasing pressure difference in the medium term. It tends to be stable in the later. The time of drainage channels to form homogeneous core is earlier than heterogeneous core. After the drainage channel, differential effects on heterogeneous core than homogeneous core of instantaneous drainage water.

Simulating CO2 and Viscosity Dissolver Assisted Steam Flooding Technology in Extra-Heavy Oil Reservoir by Using 3-D Physical Modelling

The macroscopic fluid flow mechanism of enhanced oil recovery (EOR) by CO 2 and viscosity dissolver assisted steam flooding technology for horizontal well (HDCS) is studied using “the 3-D physical modeling system of a complicated driving system under the realreservoir condition (high temperature and high pressure conditions) for EOR”. The production performance, pressure field and saturation field are measured with a differential pressure unit and saturation measuring probes. The resistance increased, the pressure increased and the flow direction changed under the physical and chemical actions of adsorption and the retention of the tannin extract. The tannin extract changed the flow direction from the main stream to the remaining oil regions on either side and displaced the remaining oil. The steam flooding not only displaced the residual oil in the main stream but also displaced the oil on either side by enlarging the swept volume from the main stream to the side.

A New High-Temperature Gel for Profile Control in Heavy Oil Reservoirs

Controlling the phenomenon of steam channeling is a major challenge in enhancing oil recovery of heavy oil reservoirs developed by steam injection, and the profile control with gel is an effective method to solve this problem. The use of conventional gel in water flooding reservoirs also has poor heat stability, so this paper proposes a new high-temperature gel (HTG) plugging agent on the basis of a laboratory experimental investigation. The HTG is prepared with nonionic filler and unsaturated amide monomer (AM) by graft polymerization and crosslinking, and the optimal gel formula, which has strong gelling strength and controllable gelation time, is obtained by the optimization of the concentration of main agent, AM/FT ratio, crosslinker, and initiator. To test the adaptability of the new HTG to heavy oil reservoirs and the performance of plugging steam channeling path and enhancing oil recovery, performance evaluation experiments and three-dimensional steam flooding and gel profile control experiments are conducted. The performance evaluation experiments indicate that the HTG has strong salt resistance and heat stability and still maintains strong gelling strength after 72 hrs at 200 °C. The singular sand-pack flooding experiments suggest that the HTG has good injectability, which can ensure the on-site construction safety. Moreover, the HTG has a high plugging pressure and washing out resistance to the high-temperature steam after gel forming and keeps the plugging ratio above 99.8% when the following steam injected volume reaches 10 PV after gel breakthrough. The three-dimensional steam flooding and gel profile control experiments results show that the HTG has good plugging performance in the steam channeling path and effectively controls its expanding. This forces the following steam, which is the steam injected after the gelling of HTG in the model, to flow through the steam unswept area, which improves the steam injection profile. During the gel profile control period, the cumulative oil production increases by 294.4 ml and the oil recovery is enhanced by 8.4%. Thus, this new HTG has a good effect in improving the steam injection profile and enhancing oil recovery and can be used to control the steam channeling in heavy oil reservoirs.

The Research of Water Influx Law for Edge-Bottom Water Heavy Oil Reservoir

The Liaohe Jin 91 block has entered the late period of steam huff and puff, the entire block is seriously water invaded. At this stage the water invasion regularity for edge-bottom water of heavy oil reservoir is not clear. In Jin 91 block two well group, for example, we model the fine geological with petrel soflware, application the CMG software throughput of history matching, and combined with homogeneous core model water influx the indoor physical model experiment,to research the water influx regulation of the edge-bottom water heavy oil reservoir. The results show that the water invasion form is given priority to with bottom water coning, the Edge water tonguing is secondary, and in accordance with the experimental data at the same time, fitting out the exponential function relationship of water influx with the differential pressure and temperature, which provides a theoretical basis for promoting the development of edge-bottom water steam flooding of heavy oil reservoir.

Experimental study and pilot test of urea- and urea-and-foam-assisted steam flooding in heavy oil reservoirs

Abstract During steam flooding in heavy oil reservoirs, steam override and channeling often cause high residual oil saturation. To quantify and alleviate these phenomena, a 3-D experimental model for urea- and urea-and-foam-assisted steam flooding was designed and developed. Three comparative experiments were conducted to facilitate the identification of different effects of flooding, including conventional steam flooding (CSF). The system was switched to urea-assisted steam flooding (UASF) and to urea-and-foam-assisted steam flooding (UFASF). A comparison of specific parameters, including instantaneous oil-steam ratio (OSR), instantaneous watercut, difference in pressure between the inlet and outlet, and oil recovery, showed UFASF to be more effective than CSF or UASF with respect to flooding. As indicated by the change in temperature, the UFASF was able to control the steam override and channeling and fully extend the steam chamber effectively. This not only increased the sweep efficiency but also improved the conformance factor of the steam flooding. The experimental results of the UFASF were successfully used to guide a pilot test of the Jin-1 Block at Liaohe Oilfield, China. Results indicated that the UFASF may be a feasible means of improving the oil recovery of the steam flooding in heavy oil reservoirs.

Enhance Oil Recovery for Steam Flooding: Low-Temperature Oxidative Decomposition of Heavy Oil with Air Injection

With the increasing demand of energy, technical research of how to enhance oil recovery of steam flooding for heavy oil reservoirs has attracted widespread attention at present. Air-injection is an effective technology that has been used to improve the development effect of steam flooding in heavy oil reservoirs. The low-temperature oxidation (LTO) reaction and the high-temperature combustion reaction are the main mechanisms of air-injection technology. The high-temperature combustion reaction can decompose the heavy component in heavy oil, but it requires a higher-temperature condition, which the steam flooding process cannot offer. In addition, the LTO reaction between air and heavy oil consumes the O2, so the safety risk of explosion caused by the mixture of O2 and hydrocarbon gas can be eliminated. Nevertheless, oil viscosity will increase. During the steam flooding process, an aquathermolysis reaction occurs between heavy oil and high-temperature water, which decreases the content of the heavy compon...

ANALISIS PENGOLAHAN AIR TERPRODUKSI DI WATER TREATING PLANT PERUSAHAAN EKSPLOITASI MINYAK BUMI (STUDI KASUS: PT XYZ)

The exploration and production process of oil and its supporting operations always generates wasteas by-product. If they are uncontrolled, it might decrease the environmental quality. Thus, it isnecessary to manage and treat the waste in order to meet the regulation standard of quality andquantity. PT XYZ is an energy company, particularly oil and gas production, which its productionactivity generate a large amount of waste as well as produced water. Thus, PT XYZ must havefacilities or produced water handling plant which could minimize pollution caused by produced water.PT XYZ already has a system of produced water handling with recycling principle. After oil and waterseparation including water treating at Water Treating Plant (WTP), produced water will be used forsteam injection. This is the part of enhanced oil recovery by steam flooding in Duri Field. Besides,produced water could be used as backwash water at WTP, that is Oil Removal Filter (ORF) and WaterSoftener, which is called brine water. If the produced water and brine water is over load the capacity ofoil enhanced recovery injection, it might be disposed through injection to Disposal Well and there arecertain condition that produced water should be discharged into canal. The objective f this study is toanalyze the performance of a water treating plant in PT XYZ. Water Treating Plant is a facility fortreating produced water. Basically, WTP is on good condition and each unit has high efficiency forseparating oil and water (60-99%). Horizontal velocity at pit #A of API Separator was larger than thedesign criteria. In addition, Water Softeners have efficiency until 99% for the hardness.

Failure of large-scale pilot evaporator duct nozzle

Failure investigation was carried out on a 12'' water evaporator duct nozzle of a large-scale steam flood pilot which is used to inject steam into a heavy crude oil reservoir. The nozzle contained cracks at the pipe, shell, pad and welds. All the materials are made of UNS31803 grade 2205 duplex stainless steel. The cracks were initially formed at the welds and then propagated through the pipe, pad and shell. The cracks were running almost parallel in a straight manner. The cracks were transgranular in nature in the form of fissures associated with second phase precipitates. The results indicated that the nozzle was subjected to repeated welding thermal cycles and the heat input was relatively high, as manifested by the presence of intense heat tint, high percentage of austenite in the weld region (about 70%), and the presence of embrittling intermetallic phases. The investigation concluded that the primary reason of failure was poor welding practice, which facilitated brittle cracking. Fatigue was the mode of failure, which resulted from vibration in the piping system.

Status of electromagnetic heating for enhanced heavy oil/bitumen recovery and future prospects: A review

Abstract Thermal methods are inevitable in heavy oil/bitumen recovery. Different types of “aqueous” methods such as cyclic steam and hot water injection, in-situ combustion, hot water and steam flooding, and steam assisted gravity drainage have been widely applied over decades. Currently, non-aqueous heating methods, generally named electromagnetic, are in consideration as an alternative to the aqueous methods, which may not be applicable due to technical and environmental limitations. This technique still requires further research and field scale pilot applications to prove their technical and economic viability. In this paper, a critical discussion on the review of electromagnetic heating is presented. An attempt is undertaken to review most of the research works (computational and experimental as well as a limited number of field applications) performed over more than five decades. After evaluating aqueous and non-aqueous thermal methods, a comparative analysis is presented.

A laboratory study of enhancing heavy oil recovery with steam flooding by adding nitrogen foams

Abstract Two significant problems, steam override and steam channeling, decrease the sweep efficiency of steam to result in a lower oil recovery in heavy oil reservoirs. Thermal foam flooding, which is in fact steam flooding by adding non-condensate gas and foaming agent, presents a satisfactory effect in laboratory and field pilot. In this article, a new evaluation method was introduced to choose the optimum foaming agent for thermal foam flooding. The method considered the influence of temperature variation on the properties of foaming agent during steam flooding. Then the chosen surfactant and nitrogen were injected into the reservoir model in our experiments. The results showed that nitrogen foams effectively increased displacement efficiency of steam flooding from 43.30% to 81.24% in the single sand-pack experiment. Thermal foams can effectively improve injection profile to restrain steam injection from gravity override and steam channeling in reservoirs. Foaming agent is an important component in thermal foam flooding; on the one hand, it decreases oil–water interface tension to improve oil displacement efficiency, and on the other hand, it increases the stability of foams to improve sweep efficiency. Therefore, steam flooding by adding nitrogen foams is an effective EOR method to develop heavy oil reservoirs.

Direct perturbation of the Peng–Robinson attraction and covolume parameters for reservoir fluid characterization

Numerical simulation of enhanced oil recovery processes, such as gas and steam floods, requires that the reservoir fluid of interest is reliably modeled by use of an equation of state (EOS). Reservoir fluid characterization using an EOS can be challenging because of the uncertainties associated with non-identifiable heavy fractions, which are characterized as a few pseudo components.This paper presents a new method for reservoir fluid characterization that directly perturbs the attraction and covolume parameters of pseudo components from the n-alkanes’ values (direct perturbation from n-alkanes, or direct PnA). The direct PnA method systematically adjusts the attraction and covolume parameters of all pseudo components within a given reservoir fluid through a few adjustable parameters. As in our prior research, the ψ(=a/b2) parameter is used to ensure the proper interrelationship between the attraction (a) and covolume (b) parameters. A new approach to adjustment of the ψ parameters is developed with a linear relationship of ψ with molecular weight. The Peng–Robinson (PR) EOS is used throughout the research.The direct PnA method is applied to 84 different reservoir fluids, such as gas condensates, volatile oils, and heavy oils. Characterization of each fluid uses the saturation pressure and liquid density data at different pressures at the reservoir temperature. Other phase behavior data available are used to test the predictive capability of the fluid models developed using the PR EOS with the direct PnA method. Results show that the reservoir fluids tested are reliably characterized by the systematic control over phase behavior predictions in the direct PnA method. Unlike prior characterization methods, the direct PnA method does not require estimation of apparent critical parameters of non-identifiable heavy fractions.

Overview of technical advances that encourage domestic US tar sand development

US domestic tar sand estimated resource exceeds 60 billion barrels (bbl). Production of this resource has been insignificant. Traditional petroleum production methods cannot be applied. Tar sand is highly viscous because over geologic time it was exposed to fluid pathways whereby the light ends could evaporate. The most easily accessible reservoirs are still available. The recent advances in oil/gas production technologies that have made other non-traditional resources capable of development have yet to be applied to tar sand development. Successful tar sand development would also displace some of the considerable imports of asphalt. There are two approaches to US domestic tar sand extraction: mining and subsequent surface processing, and in situ methods. Surface extraction falls into two categories: water or solvent extraction and pyrolytic techniques. In situ extraction attempts have focused on thermal methods [steam flood, electromagnetic radiation (EMR), etc.]. The desired end product determines the extraction method. [Received: December 10, 2013; Accepted: February 20, 2014]

Adaptive Mesh Refinement for 2D Non-Isothermal Three-Phase Flows in Porous Media Comprised of Different Rock Types

In this paper we develop an adaptive mesh refinement (AMR) algorithm for solving the non-isothermal three-phase flows in heterogeneous porous media such as steam flooding in heavy oil reservoir. This porous media are made up of different rock types. The refinement criteria are proposed to overcome the difficulty that the saturation is discontinuous across the interface of two different rock types. Since the ratios of relative permeability between different rock types are found to be continuous, they are chosen as the control parameters to perform the refining and coarsening operations. The numerical examples show that the proposed AMR algorithm is fast with good accuracy.

Analysis of Factors Influencing Velocity Difference of Heavy Oil Reservoir Gravity Drive

Based on the assisted gravity draining steam flooding and the development technology of drive drain compound, using computational fluid dynamics software ANYSY CFX to analyze the impact of the oil reservoir thickness、density of the crude oil 、oil viscosity and oil saturation on the seepage velocity difference. Research shows that: These factors have a significant impact on the flow velocity difference Research results provide reference for seepage study of gravity drive of heavy oil .

The effect of heterogeneity and well configuration on the performance of hot water flood

Abstract This study investigated the performance of hot water injection in several stochastically-generated permeable media using different well configurations and initial oil viscosity. The reservoir investigated is typical of a Middle Eastern heavy oil reservoir with heterogeneity and fluid properties that differ significantly from one location to another. The reservoir is a candidate for a thermal recovery method. However, due to the lack of fresh water to conduct steam flooding, only hot water flooding is considered in this study. Several three-dimensional heterogeneous permeability fields were generated geostatistically using the matrix decomposition method, to cover a wide range of permeability variation and correlation structure. Initially, simulations of hot water displacement were performed in all these permeable media with a multilateral horizontal well injector and a vertical producer. These results were then compared to those obtained with unheated conventional water flood. Investigations were then carried out to study the sensitivity of the displacement performance to the initial oil viscosity and to other well combinations. These well combinations consisted of vertical producer-vertical injector in a five-spot pattern and horizontal injector-vertical producer in a line-drive pattern. Results show that the performance of hot water injection is strongly affected by the degree and structure of reservoir heterogeneity. Regardless of the permeability variation and the correlation structure, the use of vertical wells in a five-spot pattern was found to be the most suitable well configuration to develop this reservoir. The combination of high permeability variation and high correlation length significantly reduces the displacement performance of horizontal or multilateral wells.

Applied Research of Heat Self-Generated CO2 Technology in Steam Huff and Puff

Heat self-generated CO2 technique is proposed, which is focused on the problems of recovery difficulty, poor effect steam soaking and so on for heavy oil reservoirs. This technology is combining of steam flooding and gas flooding and so on. Its main mechanism is the application of steam heating blowing agent to generate a large volume of gases (including CO2, NH3, etc) in the formation. While some of these gases acting with the oil to reduce the oil viscosity, some form miscible flooding to reduce water interfacial tension, so as to achieve the purpose of enhancing oil recovery. An optimized selection of the heat blowing agents was performed. By comparison the difference before and after the reaction of blowing agent solution, the increase of alkaline is occurred after the reaction, and is helpful to reduce oil viscosity and lower interfacial tension, etc. Studies indicate that heat-generating CO2 flooding technology can get a maximum viscosity reduction rate of 76.7%, oil-water interfacial tension decreased by 54.77%, further improve oil recovery by 4.17% based on the steam drive, which shows a technical advantage toward conventional EOR method. The field experiments indicate that the technique can greatly improve the oil production, which will provide a powerful technical supporting for the efficient development of heavy oil.

Characteristics Analysis of Cold Foam and Hot Foam During Steam Flooding in Heavy Oil Reservoirs

Hot foam with steam following in the process of foam injection and cold foam without steam following are investigated. Through static and dynamic evaluation experiments, foaming agents are screened and the effects of factors on foam blocking capacity are studied. Then the blockage and displacement experiments of cold and hot foam are conducted. The results show that cold foam has larger blocking strength and is preferred to start up low permeability contrast layers. Hot foam is recommended to use in higher ones and due to the temperature sensitivity of heavy oil, the oil production of hot foam is larger than that of cold foam, whatever continuation or slug injection.

A workflow for risk analysis and optimization of steam flooding scenario using static and dynamic proxy models

Abstract Heavy oil reservoirs are full of uncertainties because of the difficulties in fluid and core sampling as well as well testing operations. Therefore, making any decision on development plan of heavy oil reservoirs under strong uncertain conditions needs risk analysis. Different thermal processes like steam injection have been used for the recovery of heavy oil. Because of high steam generation costs, it is necessary to optimize the process. But both risk analysis and optimization are very time consuming and expensive tasks as they both need too many simulation runs. Creating a proxy model, which replaces the simulator and emulates simulator outputs very fast, seems to be a good solution to this problem. Different static proxy models have been used to-date, which can optimize the process only at one certain time of simulation and they are not valid for other times. In this study for the first time dynamic or time dependent proxy models are used for uncertainty analysis and optimization. The term dynamic or time-dependent proxy model is a response surface of desired objective parameters, which is valid for the whole time interval of the process. This study demonstrates the application of artificial intelligence for optimization of steam flooding using dynamic proxy models. A new time-dependent artificial neural network is introduced as a dynamic response surface. By coupling this response surface with genetic algorithm, optimum injection conditions such as steam injection rate, steam quality, and also optimum injection time are obtained in a no-dip layered heavy oil reservoir. The proposed workflow is a rapid and cost-effective tool for risk analysis and optimization of steam flooding in heavy oil reservoirs.

High-Pressure Direct-Fired Steam-Gas Generator (HDSG) for Heavy Oil Recovery

High-pressure direct-fired steam-gas generator (HDSG) is to produce multiplex thermal fluid (contains water, CO2, N2 etc.) through efficient direct-contact heat transfer, which would utilize the flue gas heat and reduce the gas emission caused by ordinary boiler. Furthermore, the multiplex thermal fluid can promote the heavy oil recovery by both steam flooding and miscible flooding. This paper introduced three kinds of HDSG: pressurized submerged combustion vaporization (PSCV), multiplex thermal fluid generator and supercritical hydrothermal combustor, which are different in work pressure and method of mixing water and flue gas. Then, we discussed the economic efficiency of HDSG used for heavy oil recovery and concluded that although the pressurization of fuel and oxygen would cost as much as the energy saved by utilizing the flue gas heat, using HDSG for heavy oil recovery has other incalculable benefits such as miscible flooding, waste water treatment and reduction of heat loss through injection well. Finally, we indicated that supercritical hydrothermal combustor will be the trendy of HDSG and pointed out the future research should be carried out on the heat and mass transfer characteristic of the combustion field when water presents and the combustion stability and completeness when pressure increases.

Pilot Test Study on Steam Flooding of Jin-45 Block Flooded Area

After 30 years’ steam huff and puff, Jin-45 block has been flooded seriously, to continue relying on the steam simulation has been difficult to have a effective development and it has been exposed a series of questions [1-3] . According to the serious reservoir water influx, the development of huff and puff can’t develop questions effectively and sustainably, it’s necessary to find an effective approach to take over it . In order to demonstrate the feasibility of steam-flooding in flooded area, we need to built geologic model by Petrel, to finish history matching and steam flooding test by CMG [4-8] . Optimize the layer series of development and the projects of injecting, finally to formulate the reasonable flooding project that to solve the replacing of the last stage’s development approach in water flooded reservoir turnover, to improve block recovery ratio, and provided reference of huff and puff into steam drive in water flooding [5-11] . Key words : Water flooding; Steam flooding; Numerical simulation; Scheme optimization